Giant colossal squid
The largest invertebrates in the world and a mystery
Happy Earth Day! April 22nd, OK I’m a day late.
If you know anybody in Salem, OR, I’m doing my Fly Through Time show at the Chemeketa Auditorium Sunday May 4 at 2:00. https://bit.ly/43Xgy3e
We humans think we’re cool for having a backbone? Well congratulation my fellow worms-with-limbs, Chordates (animals with backbones) at 65,000 described species, rank fourth in biodiversity among the phylums of life after Arthropods (1,250,00 species) Flowering plants (300,000) and Mollusks (85,000). When most people think of animals they think of vertebrates, animals with backbones, —fish, mammals, reptiles, amphibians and birds, but in reality less then 5% of known species of animals are vertebrates. 96%, probably more, are invertebrates.
Now to be fair to us narrow-minded spinal taps, most invertebrates are small and most large animals, the ones that grab our notice, bigger then a loaf of bread say, are chordates; they got backbone. Sure there are one million described species of insects versus only 65,000 chordates, but insects are small.
But there are some really big invertebrates, mostly in the mollusk phylum. What is the largest invertebrate in the world?
Don’t google, just guess. I’ll wait.
If you said the giant squid or the colossal squid then 10 points for team inverti-braniac. Giant squid (Architeuthis dux) are the longest, reaching at least to 13 meters, longer than a school bus, and weighing up to at least 600 pounds. Colossal squid (Mesonychoteuthis hamiltoni) are shorter but bigger bodied, reaching weights of at least 1100 pounds. Those are conservative numbers, you can see much longer estimates for giant squid length for instance. It’s all murky because see, we’ve almost never seen these enormo-critters. Both of them live in the deep dark, in the midnight and twilight zones of the ocean, and we know very little about them. Dead ones wash up on shore every few years and dying live ones and juveniles have been photographed in shallow water a few times. For scientists getting video of them in their deep natural habitat is the holy grail.
Colossal Squid, the heaviest invertebrate in the world, lives only in the Southern ocean and is especially unknown. It was photographed in its habitat for the first time only a month ago by a robotic submersible operated by the Schmidt Ocean Institute.
It is beautiful and gives us some new information about their luminescent abilities but it is alas only a small juvenile, just under a foot long. Although we have had evidence of their existence for a 100 years there is still no photo or video of an adult colossal squid in their habitat. We can only guess how they hunt, how they move.
There have been multiple popular science books recently about the high intelligence of octopuses, cephalod cousins to the squid. Octpuses are intelligent problem solvers who evolved their intelligence completely separately from vertebrates. Thus they are the closest we have to alien intelligence and lots of people are studying their intelligence, mostly by observing them in captivity. The largest species of octopus, pacific giant octopus, common in shallow water off the west coast USA, tops out at about 4 meter length, 50 pounds in weight, so they are much smaller. We have no idea if giant squid or colossal squid is that intelligent or more intelligent, we’ve never observed any of their behavior.
We know so little about any of the animals in the deep dark ocean that makes up the majority of habitable space on earth because the pressures there are very unfriendly to human life. I recently got my PADI scuba license and have been down to 22 meters, a depth that caused my ears to be plugged up for a few weeks despite following the safety stop protocols. Recreational scuba divers are limited to 40 meters deep, there is enough light for photosynthesis down to about 200 meters. (Photosynthesis being the energy source for almost all life on earth) but the average depth of the ocean is over 3600 meters and there is life all the way down. The bottom of the Mariana Trench, the deepest place in the ocean at 10,935 meters, is almost as difficult for humans to visit as the moon, and visited just as rarely. But every time people have been there, they’ve seen life down there.
Giant squid are much more common than colossal squid, they live all over the world, and we’ve known about them for centuries. Fisherman and whalers have reported rare sightings for centuries, they are a critter of myth, the Kraken. We have long know that sperm whales hunt giant squid, sperm whale ambergris often has many squid beaks and their skin sometimes has long tentacle sucker scars, evidence of battles that have never been observed. We know that giant squid have large brains and their eyes are bigger than basketballs. Colossal and Giant Squid have the largest eyes in the world, larger than whales or any other vertebrate. Giant squid have 8 long tentacles and two more really long tentacles that they use for feeling and grabbing. No giant squid had ever been photographed alive in its habitat until 2004.
In 2004, after a 3 year search, a team of Japanese scientists used the sperm whales to successfully find them. Depth loggers attached to sperm whales found them regularly diving to 1000 meters during the day and 500 meters at night, presumably hunting giant squid. This is evidence that giant squid participate in the largest migration of animals in the world. called the Diel Vertical Migration. Every night all kinds of fish, mollusks, crustaceans and others who live in the dark twilight zone migrate up to feed on plankton and fish in richer shallower waters. Then they swim back down to hide in the dark deep through the day.
The Japanese team sunk large bait and cameras to the whales daytime hunting ground 900 meters under the sea surface. The bait was attacked by an 8 meter (25 feet) long giant squid. The squid became hooked and swam madly about, dragging the hook, bait, and cameras up to 600 meters deep and then back down to 1000 meters deep. Finally it broke off one of its feeding tentacles and escaped, probably to die.
I find it fascinating that there are creatures so large that we know little about, the world is still full of mystery. Giant and colossal squid come from a world, the deep ocean, that we know very little about and that we hopefully haven’t yet had a large effect on. We are changing and killing off life in the shallow ocean waters at an astounding rate. Primarily through fishing, —we have removed the majority of large apex predators, fish and marine mammals, all over the world—, and secondarily through pollution and global climate change. What effect we are having on the denizens of the deep ocean, we have no idea. We have overfished deep-water fish a few times and found out that they recover much more slowly than shallow water fish stock . Life living in the cold deep generally operate at a slower energy level. A handful of robotic deep water submersibles operating around the world are bringing in more information about life in the deep but we’re still in the beginning phases.
Alas, for oceanic scientists in the US, it’s not a good time. The Trump administration has so far proposed cutting about three quarters of all National Oceanic and Atmospheric Administration research money. They are especially trying to eliminate all global warming related research. Cutting this research to save money is like shooting your foot off to save weight in my opinion. The NOAA is involved in 13 cooperative research arrangements where US government money and private money are combined to conduct expensive ocean and atmosphere research. They want all this to go away. Whether they succeed in cuts this large is unknown at this time but the freeze they have put on funds for 3 months now is already hurting research.
We live on the only blue planet around, covered in water and a brain-splattering diversity of life that still hides all kinds of mysteries. Happy Earth Day and thank you for reading.